The invention relates to corrective eye surgery and in particular to refractive surgery using part of a donor cornea grafted in front of the patient's cornea known as epikeratophakia.
Epikeratophakia is a relatively new concept in refractive surgery developed by Dr. Herbert Kaufman. It has been dubbed "the living contact lens", and has been offered as a simple and safer process than keratomileusis technique developed by the Instituto Barraquer of Bogota, Colombia. Instead of reshaping the anterior portion of the patient's own cornea as in the keratomileusis process, epikeratophakia uses a slice of donor cornea shaped into a lenticle and then sutured to the front of the patient's own cornea.
FIGS. 1 and 2 diagrammatically illustrate the prior art in the practice of epikeratophakia. FIG. 1 shows a slice 1 of a donor's cornea 2 being shaved off by means of a micro-keratome knife 3. The knife 3 has a sole 4 which, when applied to the cornea 2, flattens its top. An oscillating blade 5 passing through a slot 6 in the sole 4 cuts a slice 1 of the cornea which in its natural unrestrained shape appears as shown in FIG. 2. The posterior or concave face of the slice or lenticle 1, is then ground to obtain the proper refractive correction required by the patient by removing the shaded area 7. On the patient's cornea 8 a peripheral groove 9 is cut to receive the base 10 of the corrected lenticle 1, which is then sutured to the patient's cornea 8. The shape and width of the peripheral groove 9 is normally achieved by two slicing operations. The first is directed perpendicularly to the axis of vision to form the base 11 of the groove. The second is directed parallelly to the axis of vision to form the inner wall of the groove 12. The matching of the base 10 of the lenticle 1 with the peripheral groove 9 is often difficult to control. The cutting of the groove itself by means of two types of trephines is a difficult operation which requires great skill and precision.